An efficient multi-scale lattice model approach to screening nano-porous adsorbents

We present a multi-scale, hierarchical, approach for developing lattice models to estimate adsorption in nano-porous sorbents, derived on the basis of underlying atomistic potentials. This approach is a generalization of earlier work in zeolites (where the specific adsorption sites are easily definable) to encompass both specific as well as diffuse adsorption; the latter often dominates in the case of nano-porous metal-organic frameworks (MOFs). In conjunction with appropriately coarse grained guest-guest interactions, we demonstrate that our lattice approach offers semi-quantitative to quantitative agreement as compared to fully atomistic simulation from the low pressure regime through saturation. However, it also yields orders-of-magnitude acceleration versus the latter, thus enabling high-throughput screenings of both non-polar and polar adsorbates with high efficiency. We also show how our lattice model can be extended to facilitate rapid, qualitative screening of transport properties via appropriate calibration. Although our example applications focus on CO(2) adsorption in MOFs, this approach is readily generalizable to various nano-porous materials (MOFs, zeolites...) and guest adsorbates (CO(2), H(2), hydrocarbons).